Google Chrome - how can i programmatically enable chrome://flags some of the modules from disable mode to enabled mode?

Question

How can I automate the setting of chrome flags to enable few modules?

I have application designed which requires on open the chrome://flags few modules enabled, othe

Answer 1

Almost every Chrome flag can be set via the command line. Here is a quite exhaustive list of command line parameters, but also keep in mind that there would be even more in newer versions!

EDIT: Here is the Comprehensive, up-to-date list of Chrome command line switches

So basically you would launch chrome with these command line flags already set. That's the best way to go about it.

You cannot manually set this using Javascript or other behavior. The only way you can set this programmatically (other than command line flags) is to use Capybara (a tool that can open and control browsers, generally used for running automated tests), open Chrome and then manually navigate to "chrome://flags" and click the necessary combo boxes.

EDIT: Watir is also as good as Capybara

Watir is another browser automation framework (similar to Capybara) but is much easier to setup and start with. Here are examples on how you would open a web page and select a combo box, and here are instructions on using it with Chrome. You can write a single ruby file which looks like:

require 'watir-webdriver'
browser = Watir::Browser.new :chrome
browser.goto "chrome://flags"
browser.select_list(:id => <combo box id>).select("Enabled")
...

Persisting the Flags when using WebDriver

Chrome has the --user-data-dir switch which is where all the profile settings are saved. The default directories that Chrome uses (on Windows/Mac/Linux) [is documented here. Generally, WebDriver launches with a temporary --user-data-dir, and later deletes the temporary folder after use. So whatever flags you set will be lost when you run Chrome again! So set --user-data-dir to your user's default profile directory, and then whatever flags you set will be persisted.

Edit 2: Added comprehensive list of chrome command line flags

Edit 3: Added instructions for persisting the flags in Webdriver

Answer 2

Rooting about in the chrome://flags screen I found something interesting in an included JS file :

/**
 * Invoked when the selection of a multi-value choice is changed to the
 * specified index.
 * @param {HTMLElement} node The node for the experiment being changed.
 * @param {number} index The index of the option that was selected.
 */
function handleSelectChoiceExperiment(node, index) {
  // Tell the C++ FlagsDOMHandler to enable the selected choice.
  chrome.send('enableFlagsExperiment',
              [String(node.internal_name) + '@' + index, 'true']);
  requestFlagsExperimentsData();
}

chrome.send is indeed a valid method,

Here is another snippet form the same file (chrome://flags/flags.js)

/**
 * Asks the C++ FlagsDOMHandler to restart the browser (restoring tabs).
 */
function restartBrowser() {
  chrome.send('restartBrowser');
}

Manually calling chrome.send ('restartBroswer') did indeed restart the browser.

I think this provides all the facilities you need to automate the setting of the flags, you will need to trawl through the chrome://flags source to find the flags you need and then set up the appropriate chrome.send calls.